refractometer help

[Yariv Reef Aquarium]

Hello reefers

i have 2 type of refractometer, one where it says 20 degrees, and another one where there s no temperature written inside when you look at the salinity result, i was sure my tank was at 1.025, but the one where the 20degrees show alway give me 1.029.

will be glad to have your experience with it , what is my salinity level in my reef ? my tank is set at 25 degres.

thanks
Yariv

 

[redfishbluefish]

First off with either refractometer, you need to calibrate it using 53mS/cm (35ppt) calibration fluid. HERE's an example from BRS, but other brands do exist. Do not use RO/DI water to calibrate.


Now as far as the two refractometers, I'm going to make some assumptions. The one marked 20C, the samples need to be at 20C to get an accurate reading. The other one I'm going to guess is ATC. Do you see those letters on the refractometer? They mean Automatic Temperacture Compensation, and the refractometer will adjust to whatever the temperature of the sample might be.

Hope this helps. If not, you might wish to read THIS article from Dr. Randy.